The picture in a computer and TV screen screen is made up of tiny colored squares called pixels. If you look close enough, you'll be able to see the pixels on a TV screen, but not a computer screen, as the pixels are too small see. In a TV and computer screen, the electronic equipment switches all the colored pixels on and off at a rapid pace. The light from the screen travels to your eyes and into your brain, tricking it into thinking it's moving. In a digital camera, it's the exact opposite. Light from the thing you're photographing zooms into the camera lens. It hits the image sensor chip, breaking it up into millions of pixels. The sensor measures the color and brightness of each pixel and stores it as a number. In short, your photo is a huge string of numbers, describing the details of each pixel it has. - Audrey